/**
 * 文本、脚本、图片卡片共用的节点组件。组合标题、内容、通用变换容器与四向连线入口。
 * 编辑通过作用域动作接口发出，不直接写文档；旧连线的无名连接点仍保留用于兼容定位。
 */
"use client";
import { CanvasImage } from "./canvas-image";
import { managedImageSource } from "@/lib/canvas-v2";

import { useRef } from "react";
import { Handle, Position, useViewport, type NodeProps } from "@xyflow/react";
import { FileText, Image as ImageIcon, Type } from "lucide-react";
import { elementCapabilities } from "@/lib/canvas-elements";
import { nodeDirections, type CanvasNode } from "@/lib/canvas";
import { NodeTitle } from "./node-title";
import { CanvasTextEditor } from "./canvas-text-editor";
import {useScopedNodeEditing} from "./node-editing";
import styles from "./canvas.module.css";
import { TransformableNode } from "./transformable-node";
export { NodeEditing } from "./transformable-node";

/** 方向字符串到ReactFlow几何方位的映射，与nodeDirections的稳定Handle ID配套。 */
const positions = { top: Position.Top, right: Position.Right, bottom: Position.Bottom, left: Position.Left };
/** 四向连接入口的中文可访问名称，不参与端点数据编码。 */
const labels = { top: "上方", right: "右侧", bottom: "下方", left: "左侧" };

/** 按kind选择图片或文本编辑器，并显示对应标题图标；selected影响样式及连接操作入口。
 * 指针点击连接点可打开分支菜单，拖动则留给ReactFlow创建连接。 */
export function MaterialNode(props: NodeProps<CanvasNode>) {
  const { id, data, selected } = props;
  // Headless目标携带元素生命周期与归属；旧渲染回调经过作用域检查，避免迟到事件编辑已替换的对象。
  const editing = useScopedNodeEditing(id,data.__headlessTarget);
  const { zoom } = useViewport();
  // 以卡片宽度（默认260）×视口缩放×设备像素比估算显示成本；1024以内优先预览源。
  const preview = (props.width || 260) * zoom * (typeof window === "undefined" ? 1 : window.devicePixelRatio || 1) <= 1024;
  // 仅记录连接点按下的屏幕坐标，用小于5px的位移区分点击与拖动；不把它写进文档或history。
  const pointerStart = useRef({ x: 0, y: 0 });
  const Icon = data.kind === "image" ? ImageIcon : data.kind === "script" ? FileText : Type;
  // 旧target/source Handle禁用新连接但保留定位；四向Handle使用方向作ID，选中时允许开始连线。
  // 指针点击还检查branchable能力和位移；键盘Enter/空格使用Handle中心打开菜单，由动作层再处理合法性。
  // 点击/按键停止冒泡，避免分支操作同时触发节点或画布交互；文本内容的编辑生命周期由子组件负责。
  return (
    <TransformableNode {...props} className={`${styles.node} ${selected ? styles.selectedNode : ""}`}>
      <header className={styles.nodeHeading}><Icon size={13} /><NodeTitle id={id} renderedTarget={data.__headlessTarget} title={data.title} selected={selected} /></header>
      <Handle type="target" position={Position.Left} className={styles.legacyHandle} isConnectable={false} />
      {data.kind === "image" ? <CanvasImage id={id} className={styles.image} src={managedImageSource(data.src, preview)} title={data.title} /> : (
        <CanvasTextEditor id={id} data={data} selected={selected} />
      )}
      <Handle type="source" position={Position.Right} className={styles.legacyHandle} isConnectable={false} />
      {nodeDirections.map((direction) => <Handle key={direction} id={direction} type="source" position={positions[direction]}
        className={styles.centerHandle} isConnectableStart={selected}
        aria-hidden={!selected} aria-label={`从${labels[direction]}连接节点`} role="button" tabIndex={selected ? 0 : -1}
        onPointerDown={(event) => { pointerStart.current = { x: event.clientX, y: event.clientY }; }}
        onClick={(event) => {
          event.stopPropagation();
          if (selected && elementCapabilities(data.kind).branchable && Math.hypot(event.clientX - pointerStart.current.x, event.clientY - pointerStart.current.y) < 5)
            editing.branch(id, direction, { x: event.clientX, y: event.clientY });
        }}
        onKeyDown={(event) => { if (selected && (event.key === "Enter" || event.key === " ")) { event.preventDefault(); event.stopPropagation(); const rect = event.currentTarget.getBoundingClientRect(); editing.branch(id, direction, { x: rect.x + rect.width / 2, y: rect.y + rect.height / 2 }); } }}>
      </Handle>)}
    </TransformableNode>
  );
}